Heating and air conditioning units or other operating equipment frequently are mounted on a roof of a building. This type of mounting not only enables one to conserve space within the interior of a building, but provides improved air flow for the unit as well as a central, easily accessible location for ductwork and related piping and electrical connections, as well as maintenance.
In order to mount such operating equipment onto the roof, they are typically supported on a rigid support structure that itself is fastened to the roof. Normally, the support structures vary in size and shape and are constructed or assembled on site. Alternatively, a specific support structure designed for a particular roof shape and a particular heating and/or air conditioning unit is provided by the unit's manufacturer. These structures are designed to provide a relatively level mounting structure for the piece of equipment being mounted.
Normally, these structures do not provide any adjustability for different roof conditions or different pieces of equipment. For example, the pitch as well as the composition of the roof's surface frequently varies from job site to job site. These existing support structures, however, are non-adjustable; each is used for either a flat roof or a pitched roof for a specific piece of equipment which is not interchangeable for use under varying roof pitch conditions or different operating equipment. Examples of such support structures are described in U.S. Pat. Nos. 3,521,414 and 4,399,975.
Additionally, it is sometimes necessary to further level the support structure with respect to the horizontal ground plane after it is fastened to the roof in order to provide a level engagement surface for the operating equipment, i.e., a heating and/or air conditioning unit. With existing support structures, if a small amount of adjustment is necessary, shims or the like can be positioned about the support structure until the structure is satisfactorily leveled. However, if a larger adjustment is necessary, the structure itself must be significantly modified or replaced with a new structure.
Support structures for adjustably mounting operating equipment on a pitched roof of a building are also known. One such support structure is described in U.S. Pat. No. 3,742,659. In that patent, an apparatus for mounting equipment on a roof is disclosed having cooperating compartmented members that pivot on each other to form a level platform. Since the compartmented members are pivotally secured at one end, they are only capable of adjusting in one direction. Additionally, since the apparatus is tapered from front to rear, it is not capable of providing a level platform on a relatively level roof surface.
It would therefore be advantageous to provide an adjustable roof curb that can be adjusted in a plurality of directions in order to adapt to different roof pitches including a flat roof surface and which can be used with a variety of types of operating equipment.